First island colonisation by Hystrix subcristata (Mammalia, Rodentia): fossil evidence from Pleistocene, southern Taiwan

Fossil records of porcupines ( Hystrix ) from island environments in East Asia have never been reported, leaving their Pleistocene dispersal and biogeographic history poorly understood. This study describes fossil remains of Hystrix subcristata from the Chochen–Tsailiao locality, southwestern Taiwan. The locality, part of the Chiting Formation in Tainan, is dated to the Middle Pleistocene. The collection includes a well-preserved upper molar (M1/2), a lower last premolar (p4), a fragmentary lower molar (m1/2), and three fragmentary incisors. Biometric analysis indicates that the Chochen–Tsailiao specimens are smaller than H. refossa but larger than H. lagrelii and H. vinogradovi , and closely comparable in size to H. subcristata . Morphological features further corroborate this identification. This discovery is the first record of H. subcristata from Taiwan, representing both its easternmost known occurrence and the first island evidence for the genus, contrasting with all prior records which consisted only of mainland forms.